1. Field of the Invention
The invention relates to a circuit for correcting variation in voltage (hereinafter referred to as voltage variation correction circuit).
2. Description of the Related Art
FIG. 2 shows a conventional voltage supply circuit. The voltage supply circuit has an input terminal 1 to which a reference voltage Vref is externally inputted. The input terminal 1 is connected to an operational amplifier 2 configured as a voltage follower. The input terminal 1 is connected to a non-inverting input terminal of the operational amplifier 2 while an output of the operational amplifier 2 is connected to an inverting input terminal thereof. The output of the operational amplifier 2 is connected to an output terminal 3. A load circuit 4a is connected between the output terminal 3 and a ground voltage GND, and a load circuit 4b is connected between the output terminal 3 and a power supply voltage Vdd. As a result, it impossible to supply power having the same voltage as the reference voltage Vref from the output side of the operational amplifier 2 to the load circuits 4a, 4b without requiring a power from the reference voltage Vref, which is supplied to the input terminal 1.
However, there is the following drawback in the conventional circuit. Even if loads in the load circuits 4a, 4b are varied, a voltage at the output terminal 3 need be kept constant. It is necessary to increase an output capacity of the operational amplifier 2 so as to keep the voltage at the output terminal 3 constant. If the output capacity is increased, the operational amplifier 2 always consumes much power, which prevents the conventional circuit from saving or reducing a power consumption.